The first domino of what figures to be an offseason filled with sweeping changes for the New York Yankees will topple over Friday afternoon when Andy Pettitte announces his retirement after 18 seasons. The 41-year-old lefty previously retired in 2010, but returned midway through the 2012 season. This time it sounds like it will be permanent.

There are a couple ways to look at the career of Pettitte. You can remember him as a clutch postseason performer, who had a knack for pitching his best when the Yankees faced elimination. Or, if you so choose, you can forever link him to admission of taking Human Growth Hormone to help recover from an elbow injury in 2002 and his ties to former pal Roger Clemens — a legal process which is still ongoing.

The fairest way to assess the career of Pettitte is to remember him as a very, very, very good pitcher, probably a slight notch below the Hall of Fame enshrinement. His 255-152 record — a number Hall voters still use — and lifetime 3.86 ERA likely won’t be enough to get him into Cooperstown, even with his postseason success (19-11, 3.81, record 276 innings pitched) factored in. Petittte won 21 games in 1996 but lost out on the American League Cy Young award to Pat Hentgen by six votes, which fairly sums up his career.

Pettitte and Mariano Rivera — half of the Yankees so-called “Core Four” — will both hang up their spikes when this season is over. It leaves Derek Jeter, himself hobbled and 39 years old as the last member of that quartet still in pinstripes.

That might be the least of the Yankees worries. Lots of radical changes will be coming to the Bronx, but we’ll expand a lot more on that next week since the Yankees are still technically alive in the Wild Card race — 3.5 games back with nine to play. Let’s say this for now, unlike the last time the Bombers missed the postseason and spent nearly half a billion dollars on Mark Teixeira, CC Sabathia and A.J. Burnett they might not be able to buy their way back into contention for a number of factors including the $189 million luxury tax threshold.

In that regard Pettitte, who made $12 million in 2012, coming off the books will be a big help for the Yankees moving into the offseason. However it plays out, we’re approaching the last vestiges of this current Yankee era which began in 1996.

It’d be remiss not to mention that Pettitte also led to, perhaps, the greatest eruption in Mike Francesa’s radio career.

(Sorry for another Francesa clip, but that one is pure gold even four years after the fact.)